scholarly journals Phanerozoic p O 2 and the early evolution of terrestrial animals

2018 ◽  
Vol 285 (1871) ◽  
pp. 20172631 ◽  
Author(s):  
Sandra R. Schachat ◽  
Conrad C. Labandeira ◽  
Matthew R. Saltzman ◽  
Bradley D. Cramer ◽  
Jonathan L. Payne ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Fossil Record ◽  
Insect Flight ◽  
Late Devonian ◽  
Low Oxygen ◽  
Physiological Constraint ◽  
Fossil Records ◽  
Physiological Suppression ◽  
Bashkirian Stage

Concurrent gaps in the Late Devonian/Mississippian fossil records of insects and tetrapods (i.e. Romer's Gap) have been attributed to physiological suppression by low atmospheric p O 2 . Here, updated stable isotope inputs inform a reconstruction of Phanerozoic oxygen levels that contradicts the low oxygen hypothesis (and contradicts the purported role of oxygen in the evolution of gigantic insects during the late Palaeozoic), but reconciles isotope-based calculations with other proxies, like charcoal. Furthermore, statistical analysis demonstrates that the gap between the first Devonian insect and earliest diverse insect assemblages of the Pennsylvanian (Bashkirian Stage) requires no special explanation if insects were neither diverse nor abundant prior to the evolution of wings. Rather than tracking physiological constraint, the fossil record may accurately record the transformative evolutionary impact of insect flight.

scholarly journals Does time matter in phylogeny? A perspective from the fossil record

2021 ◽  
Author(s):  
Pauline Guenser ◽  
Rachel C. M. Warnock ◽  
Philip Conrad James Donoghue ◽  
Emilia Jarochowska
Keyword(s):  
Bayesian Inference ◽  
Fossil Record ◽  
Phylogenetic Inference ◽  
Late Devonian ◽  
Tree Inference ◽  
Phylogenetic Hypotheses ◽  
Range Process ◽  
Flexible Models ◽  
Intense Debate

The role of time (i.e. taxa ages) in phylogeny has been a source of intense debate within palaeontology for decades and has not yet been resolved fully. The fossilised birth-death range process is a model that explicitly accounts for information about species through time. It presents a fresh opportunity to examine the role of stratigraphic data in phylogenetic inference of fossil taxa. Here, we apply this model in a Bayesian framework to an exemplar dataset of well-dated conodonts from the Late Devonian. We compare the results to those obtained using traditional unconstrained tree inference. We show that the combined analysis of morphology and stratigraphic data under the FBD range process reduces overall phylogenetic uncertainty, compared to unconstrained tree inference. We find that previous phylogenetic hypotheses based on parsimony and stratophenetics are closer to trees generated under the FBD range process. However, the results also highlight that irrespective of the inclusion of age data, a large amount of topological uncertainty will remain. Bayesian inference provides the most intuitive way to represent the uncertainty inherent in fossil datasets and new flexible models increase opportunities to refine hypotheses in palaeobiology.

Networks

2020 ◽  
pp. 534-562
Author(s):  
Matthew O. Jackson ◽  
Brian W. Rogers ◽  
Yves Zenou
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Statistical Analysis ◽  
Labor Markets ◽  
Network Formation ◽  
Labor Market Outcomes ◽  
Negative Consequences ◽  
Social Scientists ◽  
Market Outcomes

What is the role of social networks in driving persistent differences between races and genders in education and labor market outcomes? What is the role of homophily in such differences? Why is such homophily seen even if it ends up with negative consequences in terms of labor markets? This chapter discusses social network analysis from the perspective of economics. The chapter is organized around the theme of externalities: the effects that one’s behavior has on others’ welfare. Externalities underlie the interdependencies that make networks interesting to social scientists. This chapter discusses network formation, as well as interactions between people’s behaviors within a given network, and the implications in a variety of settings. Finally, the chapter highlights some empirical challenges inherent in the statistical analysis of network-based data.

scholarly journals Relationships between Final Purchasers and Offerors in the Context of Their Perception by Final Purchasers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3271
Author(s):  
Agnieszka Izabela Baruk
Keyword(s):  
Factor Analysis ◽  
Statistical Analysis ◽  
World Literature ◽  
Empirical Studies ◽  
Primary Data ◽  
Survey Method ◽  
Chi Square ◽  
Marketing Process ◽  
Research Gap

The aim of this article was to identify the role of good mutual relationships with offerors for final purchasers, as well as define the meaning of the perception of offerors in the scope of listening to purchasers’ opinions and profiting from purchasers’ readiness to cooperate for the specificities of the prosumeric activity. A deep analysis of the world literature was used to prepare the theoretical part of this paper. The results of this analysis confirm the existing cognitive gap and research gap regarding mentioned aspects, including energy market. Empirical studies were conducted to reduce identified gaps. The survey method was used to collect primary data. The collected data were subjected to quantitative analysis, during which statistical analysis methods and tests were applied (Pearson chi-square independence test, V-Cramer factor analysis, Kruskal–Wallis test (KW), and exploratory factor analysis). The results of the statistical analysis and testing allowed the three research hypotheses formulated to be checked. Between the significance of good relationships with offerors and their perception, a statistically significant dependence was identified for all groups of offerors. The perception of offerors was a feature differentiating respondents’ opinions about the significance of good relationships with offerors for the two following groups: producers and traders. Additionally, the perception of offerors was a feature differentiating forms of prosumeric activity of respondents only for three interpurchase behaviors. The results obtained have a visible cognitive and applicability value. They contribute to the theory of marketing, as well as possibly facilitating the formation of good mutual relationships between offerors (including offerors of energy) and final purchasers as key partners cooperating with offerors in the marketing process. The approach presented in this paper has not been studied and analyzed so far, either in theoretical or in practical terms. This fact confirms its originality and value.

scholarly journals Waterlogging-Stress-Responsive LncRNAs, Their Regulatory Relationships with MiRNAs and Target Genes in Cucumber (Cucumis sativus L.)

2021 ◽  
Vol 22 (15) ◽  
pp. 8197
Author(s):  
Kinga Kęska ◽  
Michał Wojciech Szcześniak ◽  
Adela Adamus ◽  
Małgorzata Czernicka
Keyword(s):  
Target Genes ◽  
Recovery Period ◽  
Sufficient Information ◽  
Low Oxygen ◽  
Waterlogging Tolerance ◽  
Cucumis Sativus L ◽  
Waterlogging Stress ◽  
Non Coding Rna

Low oxygen level is a phenomenon often occurring during the cucumber cultivation period. Genes involved in adaptations to stress can be regulated by non-coding RNA. The aim was the identification of long non-coding RNAs (lncRNAs) involved in the response to long-term waterlogging stress in two cucumber haploid lines, i.e., DH2 (waterlogging tolerant—WL-T) and DH4 (waterlogging sensitive—WL-S). Plants, at the juvenile stage, were waterlogged for 7 days (non-primed, 1xH), and after a 14-day recovery period, plants were stressed again for another 7 days (primed, 2xH). Roots were collected for high-throughput RNA sequencing. Implementation of the bioinformatic pipeline made it possible to determine specific lncRNAs for non-primed and primed plants of both accessions, highlighting differential responses to hypoxia stress. In total, 3738 lncRNA molecules were identified. The highest number (1476) of unique lncRNAs was determined for non-primed WL-S plants. Seventy-one lncRNAs were depicted as potentially being involved in acquiring tolerance to hypoxia in cucumber. Understanding the mechanism of gene regulation under long-term waterlogging by lncRNAs and their interactions with miRNAs provides sufficient information in terms of adaptation to the oxygen deprivation in cucumber. To the best of our knowledge, this is the first report concerning the role of lncRNAs in the regulation of long-term waterlogging tolerance by priming application in cucumber.

scholarly journals 321 Role of Antibiotics in Acute uncomplicated diverticulitis, A Systematic Review and Meta-Analysis

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
A A Tahir ◽  
K M Ali ◽  
A U Khan ◽  
S Kamal ◽  
A Hussain ◽  
...  
Keyword(s):  
Systematic Review ◽  
Statistical Analysis ◽  
Treatment Failure ◽  
Hospital Stay ◽  
Meta Analysis ◽  
Dietary Advice ◽  
Duration Of Hospital Stay ◽  
Uncomplicated Diverticulitis ◽  
Acute Uncomplicated Diverticulitis

Abstract Introduction Diverticular disease is a common health problem with a wide clinical spectrum. About 75% of the patients would have uncomplicated diverticulitis. Cornerstones of treatment are antibiotics, analgesia, and dietary advice. Recent evidence has shown that its treatment is controversial, questioning the use of antibiotics. Aim is to assess the role of antibiotics in the treatment of acute uncomplicated diverticulitis. Method This is a systematic review and Meta-analysis. Literature review of the available studies was conducted using search engines like Pubmed, Medline, Embase, Google Scholar, and Cochrane databases. Statistical analysis was conducted using RevMan5.4. Results Out of 1754 records 1324 were duplicates, 430 studies were screened. 395 were further excluded.35 full text articles were assessed and in the final review 10 studies were included. PRISMA guidelines were used. Pooled OR for recurrence = 0.92 (95% CI = 0.74 to 1.13). Pooled OR for Hospital stay= -0.66 (95% CI= -1.12 to -0.21). Pooled OR for complications = 1.06 (95% CI = 0.69 to 1.64). Pooled OR for treatment failure= 1.24 (95% CI = 0.90-1.69). Conclusions We conclude that from the available evidence antibiotics have no role in reducing recurrence, complications, treatment failure, and duration of hospital stay in acute uncomplicated diverticulitis.

scholarly journals Gender Assignment in Six North Scandinavian Languages: Patterns of Variation and Change

2021 ◽  
Vol 33 (3) ◽  
pp. 264-315
Author(s):  
Briana Van Epps ◽  
Gerd Carling ◽  
Yair Sapir
Keyword(s):  
Statistical Analysis ◽  
Word Frequency ◽  
Old Norse ◽  
Gender Assignment ◽  
Feminine Gender ◽  
The Feminine ◽  
Old Swedish ◽  
Gender System ◽  
Gender Change

This study addresses gender assignment in six North Scandinavian varieties with a three-gender system: Old Norse, Norwegian (Nynorsk), Old Swedish, Nysvenska, Jamtlandic, and Elfdalian. Focusing on gender variation and change, we investigate the role of various factors in gender change. Using the contemporary Swedish varieties Jamtlandic and Elfdalian as a basis, we compare gender assignment in other North Scandinavian languages, tracing the evolution back to Old Norse. The data consist of 1,300 concepts from all six languages coded for cognacy, gender, and morphological and semantic variation. Our statistical analysis shows that the most important factors in gender change are the Old Norse weak/strong inflection, Old Norse gender, animate/inanimate distinction, word frequency, and loan status. From Old Norse to modern languages, phonological assignment principles tend to weaken, due to the general loss of word-final endings. Feminine words are more susceptible to changing gender, and the tendency to lose the feminine is noticeable even in the varieties in our study upholding the three-gender system. Further, frequency is significantly correlated with unstable gender. In semantics, only the animate/inanimate distinction signifi-cantly predicts gender assignment and stability. In general, our study confirms the decay of the feminine gender in the Scandinavian branch of Germanic.

scholarly journals Molecular clocks and the early evolution of metazoan nervous systems

2015 ◽  
Vol 370 (1684) ◽  
pp. 20150046 ◽  
Author(s):  
Gregory A. Wray
Keyword(s):  
Sensory Processing ◽  
Fossil Record ◽  
Sequence Data ◽  
Divergence Times ◽  
Molecular Clocks ◽  
Sense Organs ◽  
Animal Evolution ◽  
Nervous Systems ◽  
Nervous System Evolution ◽  
Fossil Records

The timing of early animal evolution remains poorly resolved, yet remains critical for understanding nervous system evolution. Methods for estimating divergence times from sequence data have improved considerably, providing a more refined understanding of key divergences. The best molecular estimates point to the origin of metazoans and bilaterians tens to hundreds of millions of years earlier than their first appearances in the fossil record. Both the molecular and fossil records are compatible, however, with the possibility of tiny, unskeletonized, low energy budget animals during the Proterozoic that had planktonic, benthic, or meiofaunal lifestyles. Such animals would likely have had relatively simple nervous systems equipped primarily to detect food, avoid inhospitable environments and locate mates. The appearance of the first macropredators during the Cambrian would have changed the selective landscape dramatically, likely driving the evolution of complex sense organs, sophisticated sensory processing systems, and diverse effector systems involved in capturing prey and avoiding predation.

ASYMMETRIES IN UNIVERSAL GRAMMAR The Role of Method and Statistics

2000 ◽  
Vol 22 (2) ◽  
pp. 209-228 ◽  
Author(s):  
John C. Paolillo
Keyword(s):  
Logistic Regression ◽  
Statistical Analysis ◽  
Statistical Models ◽  
Logistic Regression Model ◽  
Universal Grammar ◽  
Nonnative Speakers ◽  
Potential Explanation ◽  
Differential Learning ◽  
Grammaticality Judgments

Felix (1988) claimed to demonstrate that UG-based knowledge of grammaticality causes nonnative speakers (NNSs) to have more accurate grammaticality judgments on sentences that are ungrammatical according to UG than on those that are grammatical. Birdsong (1994) criticized the methodology employed, noting that it ignores “response bias” (a propensity to judge sentences as ungrammatical) as a potential explanation. Felix and Zobl (1994) dismissed this criticism as merely methodological. In this paper, Birdsong's criticism is upheld by considering a statistical model of the data. At the same time, a more complete logistic regression model allows a fuller statistical analysis, revealing tentative support for the asymmetry claim, as well as differential learning states for different constructions and a tendency toward transfer avoidance. These theoretically significant effects were unnoticed in the earlier discussion of this research. For SLA research on grammaticality judgments to proceed fruitfully, appropriate statistical models need to be considered in designing the research.

scholarly journals Diagnostic Modalities of Precancerous and Cancerous Cervical Lesions with Special Emphasis on CD31 Angiogenesis Factor as a Marker

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Bandana Sharma ◽  
Neetu Singh ◽  
Neena Gupta ◽  
Pavika Lal ◽  
Shefali Pande ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Pap Smear ◽  
Histopathological Examination ◽  
Cervical Lesions ◽  
Invasive Group ◽  
Angiogenesis Factor ◽  
Medical College ◽  
Obstetrics And Gynaecology ◽  
Diagnostic Modalities

Objectives. To evaluate the role of angiogenesis tumor marker CD31 in the detection of precancerous and cancerous cervical lesions and to compare its efficacy with colposcopy and histopathology. Materials and Methods. 230 patients with a suspicious looking cervix and an abnormal Pap smear attending the Outpatient Department of Obstetrics and Gynaecology of GSVM Medical College were subjected to a colposcopic examination. 180 patients with suspected colposcopic findings were subjected to a colposcopic directed biopsy. Biopsy tissues were sent for histopathological examination out of which 50 biopsied samples were sent for immunostaining of CD-31. Statistical analysis was done. Results. Comparison of microvessel density (MVD) count by haematoxylin and eosin staining (HE) and immunostaining of CD31 in preinvasive group were and , respectively, and in invasive group were and , respectively, which showed that MVD was higher by CD31 both in preinvasive and invasive group, and it was statistically significant. Conclusion. Angiogenesis is a marker of tumor progression, and CD31 fixes up vessel better as compared to HE, so aggressiveness of the tumor can be better predicted by MVD-CD31 as compared to MVD-HE.

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